Method and apparatus for processing signal in touch-screen panel

Abstract

The present invention relates to a signal processing device for a touch-screen panel, comprising: a touch driving unit that generates a driving signal with reduced harmonic components based on a sine wave and applies the driving signal to the touch-screen panel; and a touch sensing unit that detects a received signal of the touch-screen panel modulated by the driving signal; wherein the touch driving unit applies the driving signal having different frequencies to the touch-screen panel for at least two channels of the touch-screen panel, and the touch sensing unit detects a change in capacitance of the touch-screen panel by sequentially integrating the received signal corresponding to the driving signal based on a multi-capacitor.

Description

Technology Field

[0001] The present invention relates to a signal processing technique for a touch-screen panel. Background Technology

[0002] As autonomous vehicles are realized as a convergence of artificial intelligence (AI) and the Internet of Things (IoT), which are key elements of the Fourth Industrial Revolution, automotive semiconductors such as high-performance computing units and various sensors included in the vehicle are increasing, and touchscreen panels that serve as a human-machine interface (HMI) for interaction between these automotive semiconductors and the user are being installed in the vehicle.

[0003] As the usage and integration density of touchscreen panels and automotive semiconductors within autonomous vehicle systems increase, electromagnetic interference between these semiconductors is growing exponentially, and consequently, the importance of efficient electromagnetic interference mitigation is becoming increasingly prominent.

[0004] The aforementioned background technology is technical information that the inventor possessed for the derivation of the present invention or acquired during the process of deriving the present invention, and it cannot be considered as publicly known technology disclosed to the general public prior to the filing of the present invention. Prior art literature

[0005] Published Patent Application No. 10-2024-0114315 (July 24, 2024) The problem to be solved

[0006] In an embodiment of the present invention, a signal processing technique is proposed that can minimize electromagnetic interference emitted from a touchscreen panel by generating a plurality of channel-specific driving signals with reduced harmonic components and sequentially detecting a plurality of channel-specific received signals.

[0007] Specifically, in an embodiment of the present invention, in the operation of a driving controller for a touchscreen panel, the driving signal of a sinusoidal wave amplitude-modulated with a sinusoidal wave is driven using two or more frequencies to minimize electromagnetic interference problems caused by the driving signal of the touchscreen panel and to achieve excellent touch input detection performance.

[0008] Through this, the present invention aims to prevent electromagnetic interference by mitigating harmonic components of the driving signal and minimizing electromagnetic waves emitted from the touchscreen panel by modulating the amplitude of the driving signal into a sinusoidal wave. In addition, by simultaneously applying the driving signal to multiple channels at two or more frequencies and sequentially demodulating it at the receiver, a high signal-to-noise ratio characteristic is obtained, thereby providing high-precision input detection performance of the touchscreen sensor.

[0009] The problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems to be solved will be clearly understood by those skilled in the art to which the present invention pertains from the descriptions below. means of solving the problem

[0010] According to an embodiment of the present invention, a signal processing device for a touch-screen panel comprises: a touch driving unit that generates a driving signal with reduced harmonic components based on a sine wave and applies the driving signal to the touch-screen panel; and a touch sensing unit that detects a received signal of the touch-screen panel modulated by the driving signal; wherein the touch driving unit applies the driving signal having different frequencies to the touch-screen panel for each of at least two channels of the touch-screen panel, and the touch sensing unit detects a change in capacitance of the touch-screen panel by sequentially integrating the received signal corresponding to the driving signal based on a multi-capacitor.

[0011] Here, the touch driving unit may include: a driving signal generating unit that modulates the output voltage of the touch driving unit into the sinusoidal wave to generate the driving signal; and a driving signal input unit that simultaneously applies the driving signal to the at least two channels.

[0012] Additionally, the driving signal generating unit may include: a sine wave generating digital-to-analog converter that generates the sine wave by low-pass filtering a digital signal applied to the touch driving unit; and a sine wave amplitude modulating digital-to-analog converter that generates the driving signal in which harmonic components caused by the activation signal are reduced by modulating the supply voltage of the sine wave generating digital-to-analog converter into the sine wave, thereby enabling the driving signal to be output by the synthesis of the excitation signal of the sine wave and the activation signal.

[0013] Additionally, the driving signal input unit may include a timing controller for sequentially selecting the at least two channels; and a demultiplexer for simultaneously applying the driving signal to the at least two channels in response to the selection signal of the timing controller.

[0014] In addition, the driving signal input unit can initialize the sinusoidal generating digital-to-analog converter and the sinusoidal amplitude modulating digital-to-analog converter together by sequentially selecting the at least two channels when the driving signal is applied to the at least two channels simultaneously.

[0015] In addition, the driving signal input unit can correct phase mismatch between the sinusoidal wave and the amplitude modulation signal of the sinusoidal amplitude modulation digital-to-analog converter, or phase mismatch between the at least two channels.

[0016] Additionally, the touch sensing unit may include: a signal receiving unit that receives the amount of change in capacitance and converts it into a current or voltage signal; and a signal demodulating unit that demodulates the current or voltage signal according to the frequency components of the at least two channels to compensate for the magnitude of the output voltage.

[0017] Additionally, the signal demodulator may include a dual mixer that extracts a signal of a component matching the frequency of the driving signal from the current or voltage signal; and a sequential integrator that sequentially integrates the extracted signal of the dual mixer based on the multiple capacitors.

[0018] In addition, the device may further include a control unit that detects position information of the touchscreen panel based on a digital capacitance signal demodulated by a signal demodulator.

[0019] According to an embodiment of the present invention, a signal processing method performed in a signal processing device of a touchscreen panel comprises: a step of generating a driving signal with reduced harmonic components based on a sinusoidal wave and applying the driving signal to the touchscreen panel; and a step of detecting a received signal of the touchscreen panel modulated by the driving signal; wherein the step of applying includes a step of applying the driving signal having different frequencies to the touchscreen panel for each of at least two channels of the touchscreen panel, and the step of detecting includes a step of sequentially integrating the received signal corresponding to the driving signal based on multiple capacitors to detect a change in the capacitance of the touchscreen panel.

[0020] Here, the applying step may further include: a step of generating the driving signal by modulating the output voltage required in the applying step with the sinusoidal wave; and a step of simultaneously applying the driving signal to the at least two channels.

[0021] In addition, the generating step may be characterized by including: a step of generating the sine wave by low-pass filtering a digital signal applied to the touch driving unit; and a step of generating the driving signal in which harmonic components caused by the activation signal are reduced by modulating the supply voltage required in the step of generating the sine wave into the sine wave; thereby outputting the driving signal by synthesizing the excitation signal of the sine wave and the activation signal.

[0022] Additionally, the above-mentioned authorization step may include the step of sequentially selecting the at least two channels and, by the selection, simultaneously applying the driving signal to the at least two channels.

[0023] In addition, when the driving signal is applied to the at least two channels simultaneously, the step of generating the driving signal by sequentially selecting the at least two channels may be characterized by initializing the driving signal.

[0024] Additionally, the above-mentioned authorization step may include a step of correcting phase mismatch caused by the sinusoidal wave and the modulation, or phase mismatch between the at least two channels.

[0025] Additionally, the detecting step may further include: a step of receiving the amount of change in capacitance and converting it into a current or voltage signal; and a step of demodulating the current or voltage signal according to the frequency components of the at least two channels to compensate for the magnitude of the output voltage.

[0026] Additionally, the step of compensating for the magnitude of the output voltage may include: a step of extracting a signal of a component that matches the frequency of the driving signal from the current or voltage signal; and a step of sequentially integrating the signal obtained from the extraction based on the multiple capacitors.

[0027] Additionally, the above method may further include a step of detecting position information of the touchscreen panel based on a demodulated digital capacitance signal in the step of compensating the magnitude of the output voltage.

[0028] According to an embodiment of the present invention, a computer-readable recording medium storing a computer program, wherein the computer program includes instructions for a processor to perform a signal processing method performed by a signal processing device of a touchscreen panel, and the method comprises: a step of generating a driving signal with reduced harmonic components based on a sinusoidal wave and applying the driving signal to the touchscreen panel; and a step of detecting a received signal of the touchscreen panel modulated by the driving signal; wherein the step of applying includes a step of applying the driving signal having different frequencies to the touchscreen panel for each of at least two channels of the touchscreen panel, and the step of detecting includes a step of sequentially integrating the received signal corresponding to the driving signal based on multiple capacitors to detect a change in the capacitance of the touchscreen panel.

[0029] According to an embodiment of the present invention, a computer program stored in a computer-readable recording medium may be provided, wherein the computer program includes instructions for a processor to perform a signal processing method performed by a signal processing device of a touchscreen panel, and the method comprises: a step of generating a driving signal with reduced harmonic components based on a sinusoidal wave and applying the driving signal to the touchscreen panel; and a step of detecting a received signal of the touchscreen panel modulated by the driving signal; wherein the step of applying includes a step of applying the driving signal having different frequencies to the touchscreen panel for each of at least two channels of the touchscreen panel, and the step of detecting includes a step of sequentially integrating the received signal corresponding to the driving signal based on multiple capacitors to detect a change in the capacitance of the touchscreen panel. Effects of the invention

[0030] According to an embodiment of the present invention, a driving controller for a touchscreen panel drives a driving signal of a sinusoidal amplitude modulated by a sinusoidal wave using two or more frequencies and sequentially demodulates it, thereby minimizing electromagnetic interference caused by the driving of the touchscreen panel and providing high touch input detection performance. Accordingly, the present invention can minimize electromagnetic interference. Specifically, electromagnetic interference is minimized by doubly modulating the amplitude of the driving signal, which is generated as a sinusoidal waveform, into a sinusoidal wave to reduce harmonic components caused by the enable signal that is synthesized when the driving signal is applied to the touchscreen panel. In addition, electromagnetic interference problems that may occur due to phase mismatch between signals or between channels are prevented by synchronizing the phases of the driving signal and the enable signal for each channel of the touchscreen panel. Therefore, excellent electromagnetic interference mitigation performance can be provided regardless of the size and driving frequency of the touchscreen panel. Furthermore, the present invention can improve signal-to-noise ratio characteristics. Specifically, by applying a signal to multiple channels of a touchscreen panel using two or more driving frequencies and demodulating the received signal containing two or more driving frequencies within the receiver to sequentially integrate the signal of each frequency component, a larger output signal strength compared to the same signal can be obtained, thereby providing higher signal-to-noise ratio characteristics. In addition, by utilizing the multiple relationship between driving signal frequencies during the demodulation process, power consumption and area occupation can be minimized, thereby efficiently mitigating electromagnetic interference and improving signal-to-noise ratio characteristics. In conclusion, based on the excellent electromagnetic interference mitigation performance and signal-to-noise ratio characteristics, the signal processing device of the touchscreen panel of the present invention is expected to provide stable and efficient touch input detection performance in various application fields, such as modern automotive touchscreen panels or precision industrial equipment requiring electromagnetic compatibility. Brief explanation of the drawing

[0031] FIG. 1 is a block diagram illustrating the function of a signal processing device of a touchscreen panel according to an embodiment of the present invention. FIG. 2 is a diagram illustrating, in an exemplary manner, the detailed configuration of a driving signal generation unit included within the touch driving unit of the signal processing device of FIG. 1 and the electromagnetic radiation characteristics in the frequency band according to the sinusoidal amplitude modulation of the driving signal generation unit. FIG. 3 is a diagram for explaining the specific functions of the touch driving unit of the signal processing device of FIG. 1. Figure 4 is a diagram illustrating the driving signal output waveform of the touch driving unit of Figure 3. FIG. 5 is a diagram illustrating the specific configuration of a signal receiving unit and a signal demodulating unit included within the touch sensing unit of the signal processing device of FIG. 1. Figure 6 is a diagram illustrating the operation waveform of the touch driving unit of the signal processing device of Figure 1. FIG. 7 is a diagram illustrating an exemplary case in which the number of simultaneous input channels can be adjusted according to the implementation method of the driving signal input unit included in the touch driving unit of the signal processing device of FIG. 1. FIG. 8 is a diagram illustrating the driving signal output waveform of the touch driving unit of FIG. 7. FIG. 9 is a diagram illustrating an output waveform and an operation timing diagram when a signal is demodulated using the driving frequency of a signal processing device of a touchscreen panel according to an embodiment of the present invention. FIG. 10 is a diagram illustrating an exemplary case of compensating the dynamic range of an output signal by including pre-charge and continuous charging steps using a multi-capacitor-based sequential integrator of a signal processing device of a touchscreen panel according to an embodiment of the present invention. Specific details for implementing the invention

[0032] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the scope of the present invention is defined only by the claims.

[0033] In describing the embodiments of the present invention, specific descriptions of known functions or configurations will be omitted unless actually necessary for describing the embodiments of the present invention. Furthermore, the terms described below are defined in consideration of the functions in the embodiments of the present invention, and these may vary depending on the intentions or practices of the user or operator. Therefore, such definitions should be based on the content throughout this specification.

[0034] The driving method of touchscreen panels focuses on improving touch input detection performance to provide an excellent user experience, and is being developed with the goal of high signal-to-noise ratio characteristics and fast frame rates.

[0035] One of the implementation methods is high-voltage driving, which obtains excellent signal-to-noise ratio characteristics by applying a driving signal of the touchscreen panel at a high voltage of 10V or higher, thereby amplifying the magnitude of the charge signal demodulated through the panel's mutual capacitance. While this method is effective in providing excellent touch input detection performance, it has limitations in that it is difficult to apply as a vehicle touchscreen driving controller requiring electromagnetic interference mitigation, as there is a problem that the magnitude of electromagnetic waves emitted from the touchscreen panel also increases with the high input voltage.

[0036] Another method, the Code-Division Multiple Driving (CDM) technique, simultaneously drives multiple channels of a touchscreen panel by modulating the driving signal based on an orthogonal binary code matrix, and detects touch inputs from multiple channels simultaneously by demodulating them at the receiver using orthogonality. Compared to the method of driving touchscreen panels sequentially, applying the CDM method has the advantage of achieving excellent signal-to-noise ratio characteristics without using high input voltage driving signals. This is because, by driving multiple channels simultaneously, the strength of the received signal can be increased while maintaining the existing noise level. However, this CDM-based driving method has a problem in that various harmonic components proportional to the modulation frequency are included in the driving component during the process of modulating the driving signal based on the binary code matrix; these components are then emitted as electromagnetic waves from the touchscreen panel, degrading electromagnetic interference characteristics.

[0037] Another method, the frequency-division multiple driving (FDM) technique, is a method that simultaneously drives multiple channels of a touchscreen panel using signals composed of various frequencies that maintain independence between frequencies and do not cause mutual interference. The receiver reads the information for each channel by demodulating the mutual capacitance signal modulated by the driving signal according to its frequency components; in this process, multiple channels are driven simultaneously, and the signal-to-noise ratio characteristics are enhanced by the increased received signal strength, thereby providing excellent touch input detection performance. In the case of a touchscreen driving controller implemented using the FDM method, electromagnetic waves emitted from the touchscreen panel are distributed across various frequency bands due to the characteristic of utilizing various frequency components, which can mitigate electromagnetic interference; however, a Fast Fourier Transform (FFT) operator is required to demodulate each frequency component from the driving signal composed of various frequency components, which presents a limitation in that it leads to high power consumption and area occupation.

[0038] As a method to overcome these limitations, a pseudo-random pulse driving method has been proposed to drive a touchscreen panel using a pseudo-random binary sequence signal. By using a pseudo-random binary sequence signal as a driving signal, energy is not concentrated in a specific frequency band but is spread evenly across the frequency band, thereby enabling the achievement of a frequency band spreading effect. While this pseudo-random pulse driving method can mitigate electromagnetic interference issues through a simple implementation, the characteristic that square wave driving signals contain various harmonic components causes the problem of electromagnetic waves containing harmonic components being emitted directly from the touchscreen panel. Furthermore, there is a problem in that it is difficult to maintain consistent touch input detection performance due to the degradation of signal-to-noise ratio and frame rate characteristics resulting from the limitations in applying the multi-driving method implemented in conventional technology.

[0039] Accordingly, in an embodiment of the present invention, a signal processing technology is proposed that can maintain constant touch input detection performance while minimizing electromagnetic interference emitted from a touchscreen panel in the implementation of a driving controller for a touchscreen panel of a touchscreen sensor.

[0040] Specifically, an embodiment of the present invention applies a sinusoidal driving signal, which is amplitude-modulated with a sinusoidal wave, to a touchscreen panel at two or more driving frequencies that are multiples of each other in order to minimize electromagnetic interference emitted therefrom when a driving signal is applied to a touchscreen panel while maintaining constant sensing performance. By modulating the amplitude of the sinusoidal signal with a sinusoidal wave to suppress harmonic components included in the driving signal, electromagnetic interference caused by driving the touchscreen panel is minimized, and additional signal power is secured by demodulating the received signal containing two or more driving frequencies at the receiving unit and sequentially integrating it, thereby obtaining high signal-to-noise ratio characteristics.

[0041] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0042] FIG. 1 is a block diagram for explaining the function of a signal processing device of a touchscreen panel (10) according to an embodiment of the present invention.

[0043] The signal processing device of FIG. 1 may be included in an electronic device having a touchscreen panel (10), and in an embodiment of the present invention, the electronic device may include at least one of, for example, a smartphone, an e-book reader, a tablet personal computer, a laptop personal computer, a netbook computer, a desktop computer, a server computer, and a wearable device. In another embodiment, the electronic device may include at least one of network security equipment, vehicle navigation equipment, marine electronic equipment (e.g., a marine navigation device, a gyrocompass, etc.), avionics, a vehicle head unit, a point of sales (POS) of a store, and an Internet of Things device. However, the purpose of the embodiment of the present invention is to efficiently mitigate electromagnetic interference in a device that frequently performs HMI (human machine interface) interactions through various sensors. Therefore, the electronic device applied to the signal processing device of FIG. 1 may preferably include a tablet computer or a vehicle navigation device. An application for executing various operations (touch driving, touch detection, screen output, etc.) for driving a touchscreen panel (10) may be installed in such an electronic device. The application may include, for example, a smartphone application, a PC (personal computer) application, a set-top box (STB) application, a web application, an instant application, etc., and is not limited to a specific application.

[0044] As illustrated in FIG. 1, a signal processing device according to an embodiment of the present invention may include a touch driving unit (100), a touch sensing unit (200), and a control unit (300).

[0045] The touch driving unit (100) can generate a driving signal with reduced harmonic components based on a sine wave and apply the generated driving signal to a touchscreen panel (10). In an embodiment of the present invention, the touch driving unit (100) can perform the role of applying a driving signal having a different frequency to the touchscreen panel for at least two channels of the touchscreen panel (10).

[0046] This touch driving unit (100) may include a driving signal generating unit (110) and a driving signal input unit (120).

[0047] The driving signal generating unit (110) can generate a driving signal by modulating the output voltage of the touch driving unit (100) into a sinusoidal wave, and the driving signal input unit (120) can simultaneously apply the driving signal generated by the driving signal generating unit (110) to at least two channels of the touchscreen panel (10).

[0048] These driving signal generation unit (110) and driving signal input unit (120) are elements that perform the driving step during the overall touch input detection process of the touch screen panel (10) driving controller of the present invention. By applying driving signals to various channels of the touch screen panel (10), the amount of change in mutual capacitance caused by the touch input can be modulated and transmitted by the driving signal. At this time, depending on the method of driving the touch screen panel (10), the magnitude and frequency band characteristics of the electromagnetic waves emitted from the panel vary, and this causes a problem in which the risk of electromagnetic interference increases. In order to solve this electromagnetic compatibility problem, the present invention introduces a technique to suppress harmonics of the driving signal. The driving signal generation unit (110) uses a sine wave as the basic driving signal of the touch screen panel (10), which has excellent electromagnetic interference characteristics due to having fewer harmonic components compared to a square wave. However, if only a general sinusoidal driving signal is applied, electromagnetic interference characteristics may be deteriorated by the square wave activation signal and the harmonic components of the signal generated during the process of selecting and applying the channel of the touchscreen panel (10). Therefore, the driving signal generation unit (110) of the present invention minimizes electromagnetic radiation caused by the activation signal included in the driving signal and its harmonic components by modulating the activation signal when the sinusoidal driving signal is applied to the touchscreen panel (10) into a sinusoidal wave, and generates a driving signal with two or more frequencies that are in a multiple relationship for use in the touch detection unit (200). Finally, the driving signal, which is simultaneously input to multiple channels of the touchscreen panel (10) at different frequencies with phases synchronized by the driving signal input unit (120), is a sinusoidal driving signal with amplitude modulated into a sinusoidal wave, and can prevent electromagnetic interference problems by suppressing the harmonic components of the electromagnetic waves emitted by the driving signal.

[0049] The touch detection unit (200) can detect a received signal of a touchscreen panel (10) that is modulated by a driving signal of a touch driving unit (100). In an embodiment of the present invention, the touch detection unit (200) can detect a change in the capacitance of the touchscreen panel (10) by sequentially integrating the received signal corresponding to the driving signal of the touch driving unit (100) based on a multi-capacitor.

[0050] This touch detection unit (200) may include a signal receiving unit (210) and a signal demodulating unit (220).

[0051] The signal receiving unit (210) can receive the amount of change in capacitance and convert it into a current or voltage signal, and the signal demodulating unit (220) can demodulate the current or voltage signal converted by the signal receiving unit (210) according to the frequency components of at least two channels of the touchscreen panel (10) to compensate for the magnitude of the output voltage of the touch driving unit (100).

[0052] That is, the signal receiving unit (210) and the signal demodulating unit (220) perform the role of detecting when a driving signal is applied to the touchscreen panel (10) and modulates and transmits the mutual capacitance that changes according to the touch input. The received signal is a signal in which each signal modulated by two or more driving signals of different frequencies is combined and includes the corresponding frequency components as they are. The signal receiving unit (210) detects a signal indicating the amount of change in the corresponding capacitance and converts it into a current or voltage signal while maintaining the frequency information within the signal so that it can be processed by the signal demodulating unit (220). The signal demodulating unit (220) demodulates the signal and classifies the signals transmitted by each driving frequency within the signal in which the frequency components are mixed. The classified signal is transmitted by alternately selecting a sequential integrator within the signal demodulator (220) in accordance with the timing based on the detection method of the signal receiver (210). The sequential integrator utilizes multiple capacitors to control the capacitor to be integrated according to the frequency component of the currently input signal and the detection stage of the signal receiver. At this time, charge information stored in a portion of the multiple capacitors that are not currently activated is maintained, and the signal is continuously integrated based on that information during the subsequent activation stage, thereby additionally securing the dynamic range of the output voltage and improving the signal-to-noise ratio characteristics. The output voltage can be converted into a digital signal by an analog-to-digital converter and transmitted to the control unit (300).

[0053] The control unit (300) can detect position information of the touchscreen panel (10) based on the digital capacitance signal demodulated by the signal demodulation unit (220). This control unit (300) may include, for example, a microprocessor-based processing device, and can detect accurate position information by performing digital post-processing such as digital low-pass filtering using the demodulated digital capacitance signal and using various interpolation methods.

[0054] FIG. 2 is a diagram for exemplarily explaining the detailed configuration of a driving signal generating unit (110) included in the touch driving unit (100) of the signal processing device of FIG. 1 and the electromagnetic radiation characteristics in a frequency band according to sinusoidal amplitude modulation of the driving signal generating unit (110).

[0055] As illustrated in FIG. 2, the driving signal generating unit (110) has, for example, an output voltage V of a driving signal composed of a sinusoidal wave. TX ul V SINE,ENV It is possible to generate a driving signal with reduced harmonic components by modulating with a sinusoidal wave.

[0056] This driving signal generating unit (110) may include a sinusoidal generating digital-to-analog converter (112) that generates a driving signal of a sinusoidal wave and a sinusoidal amplitude modulating digital-to-analog converter (114) that modulates the amplitude of the driving signal into a sinusoidal wave.

[0057] A sinusoidal generating digital-to-analog converter (112) generates an analog sinusoidal wave by low-pass filtering a digital signal for sinusoidal generation, and a sinusoidal amplitude modulating digital-to-analog converter (114) can generate a driving signal with reduced harmonic components caused by an activation signal by modulating the supply voltage of the sinusoidal generating digital-to-analog converter (112) into a sinusoidal wave.

[0058] Accordingly, the driving signal generating unit (110) can mitigate electromagnetic interference problems by reducing the harmonic components of the electromagnetic waves emitted from the driving signal of the touchscreen panel (10). In addition, the driving signal generating unit (110) can generate driving signals having two or more frequencies in a multiple relationship by including a plurality of sinusoidal wave generating and sinusoidal amplitude modulating digital-to-analog converters.

[0059] FIG. 2 shows the electromagnetic radiation characteristics in the frequency band according to sinusoidal amplitude modulation of the dual digital-to-analog converter (112, 114), and the driving signal of the touchscreen panel (10) generated by the synthesis of the excitation signal and the activation signal includes the electromagnetic radiation caused by the frequency components constituting each signal.

[0060] Generally, since the excitation signal has a waveform of a square wave or a sine wave and the activation signal has a square wave shape, the general driving signal causes strong electromagnetic radiation on the touchscreen panel (10) according to the characteristics of the square wave containing various harmonic components. This leads to a risk of electromagnetic interference on the touchscreen panel (10). Therefore, if both the excitation signal and the activation signal are used as sine waves, electromagnetic radiation caused by harmonic components included in the driving signal can be minimized.

[0061] FIG. 3 is a drawing for explaining the specific function of the touch driving unit (100) of the signal processing device of FIG. 1, and FIG. 4 is a drawing illustrating the driving signal output waveform of the touch driving unit (100) of FIG. 3.

[0062] As illustrated in FIGS. 3 and 4, the touch driving unit (100) may include a driving signal generating unit (110) composed of dual digital-to-analog converters (112, 114) and a driving signal input unit (120) composed of a timing controller (122) and a de-multiplexer (124).

[0063] The driving signal generation unit (110) uses a dual digital-to-analog converter structure in which two sinusoidal digital-to-analog converters are stacked to suppress harmonic components of the driving signal, thereby improving the electromagnetic emission characteristics of the driving signal of the existing touchscreen panel (10) and mitigating electromagnetic interference problems caused by the driving signal. While one digital-to-analog converter generates a sinusoidal excitation signal, the other digital-to-analog converter modulates the supply voltage of the digital-to-analog converter that generates the excitation signal. Therefore, the driving signal that is finally output is represented as a composite of a sinusoidal excitation signal and a sinusoidal activation signal, and a sinusoidal driving signal can be obtained in which the amplitude is modulated into a sinusoidal value and the harmonic components caused by the activation signal are suppressed. Additionally, excellent electromagnetic interference mitigation performance can be secured by attenuating the magnitude of the harmonic components of the output of the digital-to-analog converter through a low-pass filter located at the rear end of each converter.

[0064] The driving signal input unit (120) may include a timing controller (122) for sequentially selecting at least two channels and a demultiplexer (124) for simultaneously applying a driving signal to at least two channels in response to the selection signal of the timing controller (122).

[0065] This driving signal input unit (120) can simultaneously apply a driving signal with reduced harmonic components generated by the driving signal generation unit (110) to multiple channels of the touchscreen panel (10). By inputting driving signals of different frequencies to each channel currently applying the signal, multiple electrodes of the touchscreen panel (10) can be driven simultaneously without causing interference to each other. When applying driving signals of two or more frequencies to multiple channels simultaneously, the sine wave generation and sine wave amplitude modulation digital-to-analog converters within the driving signal generation unit (110) are initialized together as the channel for inputting the signal is changed, thereby correcting phase mismatch that may occur between the sine wave and amplitude modulation signals or between channels.

[0066] FIG. 5 is a drawing illustrating the specific configuration of a signal receiving unit (210) and a signal demodulating unit (220) included within a touch sensing unit (200) of the signal processing device of FIG. 1.

[0067] As illustrated in FIG. 5, the signal receiving unit (210) receives a change in capacitance of the touchscreen panel (10), converts it into a current or voltage signal, and can compensate for the magnitude of the output voltage by demodulating the converted current or voltage signal according to the frequency components of at least two channels of the touchscreen panel (10).

[0068] This signal receiving unit (210) may include, for example, a current conveyor, a multiplexer, etc., and receives the amount of change in capacitance of the touchscreen panel (10) modulated by the driving signal, converts it into the form of current, and transmits it. The capacitance signal modulated by the touch driving unit (100) may include two or more frequency components, and the current signal converted from it also retains the corresponding frequency information. Depending on the implementation method of the signal receiving unit (210), signals from two or more channels of the touchscreen panel (10) are sequentially received and processed through the multiplexer, thereby enabling efficient power consumption and area usage characteristics.

[0069] The signal demodulator (220) may include, for example, a dual mixer, a multi-capacitor-based sequential integrator, an analog-to-digital converter (230), etc., and can separate the current signal received from the signal receiver (210) into frequency components by demodulating the current signal at the first stage of the dual mixer using a demodulation frequency that matches the frequency of the driving signal. In this process, components that are multiples of the demodulation frequency, such as double or half of the driving frequency, based on the driving frequency that is in a multiple relationship, are removed from the received signal, and only the signal of the component that matches the demodulation frequency can be preserved. This can be achieved by placing mixers according to the type of driving frequency to extract components corresponding to each driving frequency. At the second stage within the dual mixer, the current signals separated according to frequency are alternately input to the sequential integrator according to the operation stage of the receiver. Accordingly, current signals of two or more frequencies can be divided and used according to the pre-charging or charging stage, thereby being utilized to secure additional signal strength.

[0070] In the signal demodulation unit (220), two or more multi-capacitor-based sequential integrators are arranged in each channel according to the number of driving frequencies to alternately receive current signals separated by frequency components, and can go through the stages of pre-charging and charging. Additionally, according to a channel sharing method utilizing a multiplexer of the touch detection unit (200), each integrator may have two or more independent capacitors, which are opened and closed according to the operation stage, and the received signal is stored as charge in the capacitor corresponding to the currently detected channel. At this time, some of the multi-capacitors that do not correspond to the current operation stage are blocked within the circuit using switches at both ends so that the pre-stored charge information is not initialized in other operation stages, and by continuously using this in the operation stage of the corresponding capacitor, a higher output operation range can be provided based on a certain amount of pre-charged charge compared to the conventional operation method.

[0071] FIG. 6 is a diagram illustrating the operation waveform of the touch driving unit (100) of the signal processing device of FIG. 1.

[0072] As shown in FIG. 6, the control signal (CLK) of the driving signal input section DEMUX As the current driving channel on the touchscreen panel (10) changes according to the change of the signal, the initialization signal (RST) of the dual digital-to-analog converter (112, 114) is triggered, and the phases of the activation signal and the excitation signal that generate the driving signal are synchronized to form a composite signal. At this time, the driving signal generation unit (110) uses this to generate a sinusoidal driving signal with amplitude modulation as a sinusoidal wave, and depending on the type of driving frequency, two or more driving signals of frequencies that are arranged in multiples and have a multiple relationship can be generated and applied simultaneously to adjacent channels.

[0073] The driving signal input unit (120) can be adjusted so that the same driving signal cycle is allocated to each channel sharing unit in the touch detection unit (200) by applying an activation signal that repeats two or more cycles on the same channel according to the channel sharing method using the multiplexer of the touch detection unit (200). In addition, by synchronizing the initialization signal of the dual digital-to-analog converter (112, 114) with the initialization signal of the multi-capacitor-based sequential integrator of the touch detection unit (200), mismatch between signals input to the sequential integrator can be prevented.

[0074] FIG. 7 is a diagram illustrating an exemplary case in which the number of simultaneous input channels can be adjusted according to the implementation method of the driving signal input unit (120) included in the touch driving unit (100) of FIG. 1, and FIG. 8 is a diagram illustrating the driving signal output waveform of the touch driving unit (100) of FIG. 7.

[0075] The difference from Fig. 3 is that, depending on the implementation method of the touch driving unit (100), multiple sinusoidal generating digital-to-analog converters (112) are arranged, and driving signals of N frequencies generated are simultaneously applied to N channels of the touchscreen panel (10).

[0076] A signal processing device of a touchscreen panel (10) according to an embodiment of the present invention as shown in FIG. 7 can generate driving signals of two or more frequencies and apply them to the panel simultaneously, thereby allowing various frequency components to be included in the received signal of the touch detection unit (200), and can efficiently demodulate the signal using a frequency multiple relationship.

[0077] FIG. 9 is a diagram illustrating an output waveform and operation timing diagram when a signal is demodulated using the driving frequency of a signal processing device of a touchscreen panel (10) according to an embodiment of the present invention.

[0078] As illustrated in FIG. 9, the change in capacitance of a touchscreen panel (10) modulated by driving signals composed of two or more frequencies is transmitted to a touch detection unit (200) while including the corresponding frequency components. Generally, the Fast Fourier Transform used to distinguish frequencies results in significant costs in terms of power consumption and area occupation.

[0079] The signal demodulator (220) within the touch detection unit (200) can demodulate a received signal using a multiple relationship between frequencies, and a mixer can be used for the signal demodulation.

[0080] At this time, the mixer is arranged in multiple units according to the type of driving frequency and mixes the signals using a demodulation frequency that matches each driving frequency. This prevents rectification of signals that have various multiple relationships, such as double or half, with the corresponding demodulation frequency, so that they can be removed in the subsequent integration stage, while preserving only the signal component that matches the demodulation frequency as is so that it can be integrated and output.

[0081] Accordingly, the present invention can efficiently perform signal demodulation by minimizing power consumption and installation area that may occur during the demodulation process.

[0082] FIG. 10 is a diagram illustrating an exemplary case of compensating the dynamic range of an output signal by including pre-charge and continuous charging steps using a multi-capacitor-based sequential integrator of a signal processing device of a touchscreen panel (10) according to an embodiment of the present invention.

[0083] As shown in FIG. 10, the demodulation frequency (CLK) that matches the frequency components constituting the signal within the dual mixer TX,2X and CLK TX,1X Current signal (I) distinguished according to ) P,2X and I P,1XThe signal is ultimately alternately input to multiple sequential integrators arranged according to the type of driving frequency. Each sequential integrator can undergo a pre-charging stage or a charging stage by integrating signals of different frequencies, and each stage is repeated sequentially; by continuously connecting the charge amount between the pre-charging stage and the charging stage by opening and closing switches at both ends, the integrator output voltage (V) INTP,INTM The dynamic range of ) can be increased.

[0084] Additionally, the sequential integrator has multiple capacitors according to the multiplexer-based channel sharing method of the touch detection unit (200), and depending on the current operation stage, a portion of the multiple capacitors can be selected and the remainder can be blocked from the circuit using switches at both ends.

[0085] Accordingly, the multi-capacitor-based sequential integrator according to an embodiment of the present invention can improve signal-to-noise ratio characteristics by charging, maintaining, and ensuring continuity of charge independently of changes in the charging operation stage and input channel, thereby being efficient in terms of power consumption and area, and obtaining a higher dynamic range of output voltage.

[0086] According to the embodiments of the present invention described above, excellent electromagnetic interference mitigation performance can be provided regardless of the size and driving frequency of the touchscreen panel, and signal-to-noise ratio characteristics can be improved. Specifically, by applying a signal to multiple channels of the touchscreen panel using two or more driving frequencies and demodulating the received signal containing two or more driving frequencies within the receiver to sequentially integrate the signal of each frequency component, a larger output signal strength compared to the same signal can be obtained, thereby providing higher signal-to-noise ratio characteristics. Furthermore, by utilizing the multiple relationship between driving signal frequencies during the demodulation process, power consumption and area occupation can be minimized, thereby efficiently mitigating electromagnetic interference and improving signal-to-noise ratio characteristics. In conclusion, based on the excellent electromagnetic interference mitigation performance and signal-to-noise ratio characteristics, the signal processing device of the touchscreen panel of the present invention is expected to provide stable and efficient touch input detection performance in various application fields, such as modern automotive touchscreen panels or precision industrial equipment requiring electromagnetic compatibility.

[0087] Meanwhile, combinations of each block of the attached block diagram and each step of the flowchart may be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a specialized computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create a means to perform the functions described in each block of the block diagram.

[0088] Since these computer program instructions may be stored in a computer-available or computer-readable recording medium (or memory), etc., which can be directed toward a computer or other programmable data processing equipment to implement a function in a specific way, the instructions stored in the computer-available or computer-readable recording medium (or memory) may also be used to produce a manufactured item containing instruction means that perform the function described in each block of the block diagram.

[0089] And, since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on a computer or other programmable data processing equipment to create a process executed by a computer and perform the computer or other programmable data processing equipment may also provide steps for executing the functions described in each block of the block diagram.

[0090] Additionally, each block may represent a module, segment, or part of code containing at least one executable instruction for executing a specified logical function(s). Also, it should be noted that in some alternative embodiments, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may actually be executed substantially simultaneously, or the blocks may be executed in reverse order according to the corresponding function. Explanation of the symbols

[0091] 10: Touchscreen panel 100: Touch actuator 110: Driving signal generation unit 112: Sinusoidal Generation Digital-to-Analog Converter 114: Sinusoidal Amplitude Modulation Digital-to-Analog Converter 120: Driving signal input section 122: Timing Controller 124: Demultiplexer 200: Touch detection unit 210: Signal receiver 220: Signal demodulator 230: Analog-to-Digital Converter 300: Control unit

Claims

Claim 1 A signal processing device for a touch-screen panel comprises: a touch driving unit that generates a driving signal with reduced harmonic components based on a sine wave and applies the driving signal to the touch-screen panel; and a touch sensing unit that detects a received signal of the touch-screen panel modulated by the driving signal; wherein the touch driving unit applies the driving signal having different frequencies to the touch-screen panel for at least two channels of the touch-screen panel, and the touch sensing unit detects a change in capacitance of the touch-screen panel by sequentially integrating the received signal corresponding to the driving signal based on a multi-capacitor, and the touch driving unit comprises a driving signal generating unit that generates the driving signal by modulating the output voltage of the touch driving unit with the sine wave. The driving signal input unit for simultaneously applying the driving signal to the at least two channels; wherein the driving signal generation unit comprises: a sine wave generating digital-to-analog converter that generates the sine wave by low-pass filtering a digital signal applied to the touch driving unit; and a sine wave amplitude modulating digital-to-analog converter that generates the driving signal in which harmonic components caused by an activation signal are reduced by modulating the supply voltage of the sine wave generating digital-to-analog converter into the sine wave; thereby outputting the driving signal as a synthesis of the excitation signal of the sine wave and the activation signal; and wherein the driving signal input unit comprises: a timing controller for sequentially selecting the at least two channels; and a demultiplexer that simultaneously applies the driving signal to the at least two channels in response to a selection signal of the timing controller.A signal processing device for a touchscreen panel comprising, wherein the driving signal input unit initializes the sinusoidal generating digital-to-analog converter and the sinusoidal amplitude modulating digital-to-analog converter together by sequentially selecting the at least two channels when the driving signal is applied to the at least two channels simultaneously. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 In claim 1, the driving signal input unit is a signal processing device for a touchscreen panel that corrects phase mismatch between the sinusoidal wave and the amplitude modulation signal of the sinusoidal amplitude modulation digital-to-analog converter, or phase mismatch between the at least two channels. Claim 7 A signal processing device for a touch-screen panel comprises: a touch driving unit that generates a driving signal with reduced harmonic components based on a sine wave and applies the driving signal to the touch-screen panel; and a touch sensing unit that detects a received signal of the touch-screen panel modulated by the driving signal; wherein the touch driving unit applies the driving signal having a different frequency to each of at least two channels of the touch-screen panel, and the touch sensing unit detects a change in capacitance of the touch-screen panel by sequentially integrating the received signal corresponding to the driving signal based on a multi-capacitor; the touch driving unit comprises: a driving signal generating unit that generates the driving signal by modulating the output voltage of the touch driving unit with the sine wave; and a driving signal input unit that simultaneously applies the driving signal to the at least two channels; and the touch sensing unit comprises: a signal receiving unit that receives the change in capacitance and converts it into a current or voltage signal. A signal processing device for a touchscreen panel, comprising: a signal demodulator that demodulates the current or voltage signal according to the frequency components of the at least two channels to compensate for the magnitude of the output voltage; wherein the signal demodulator comprises: a dual mixer that extracts a signal of a component matching the frequency of the driving signal from the current or voltage signal; and a sequential integrator that sequentially integrates the extracted signal of the dual mixer based on the multiple capacitors. Claim 8 delete Claim 9 A signal processing device for a touchscreen panel according to claim 7, further comprising a control unit that detects position information of the touchscreen panel based on a digital capacitance signal demodulated by the signal demodulation unit. Claim 10 A signal processing method performed in a signal processing device for a touchscreen panel comprises: a step of generating a driving signal with reduced harmonic components based on a sine wave and applying said driving signal to the touchscreen panel; and a step of detecting a received signal of the touchscreen panel modulated by said driving signal; wherein the step of applying includes a step of applying said driving signal having different frequencies to each of at least two channels of the touchscreen panel to the touchscreen panel, and the step of detecting includes a step of detecting a change in capacitance of the touchscreen panel by sequentially integrating the received signal corresponding to said driving signal based on multiple capacitors; wherein the step of applying includes a step of generating said driving signal by modulating the output voltage required in the step of applying with said sine wave; and a step of simultaneously applying said driving signal to said at least two channels; and wherein the step of generating includes a step of generating said sine wave by low-pass filtering a digital signal applied to the signal processing device. A signal processing method for a touchscreen panel, comprising: a step of generating a driving signal in which harmonic components by an activation signal are reduced by modulating a supply voltage required in the step of generating the sinusoidal wave into the sinusoidal wave; thereby outputting the driving signal by synthesizing the excitation signal of the sinusoidal wave and the activation signal; and the step of applying the driving signal includes sequentially selecting at least two channels and simultaneously applying the driving signal to the at least two channels by the selection, wherein when the driving signal is simultaneously applied to the at least two channels, the step of generating the driving signal is initialized by sequentially selecting the at least two channels. Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 A signal processing method for a touchscreen panel according to claim 10, wherein the applying step includes the step of correcting phase mismatch caused by the sinusoidal wave and the modulation, or phase mismatch between the at least two channels. Claim 16 A signal processing method for a touchscreen panel according to claim 10, wherein the sensing step further comprises: a step of receiving the amount of change in capacitance as input and converting it into a current or voltage signal; and a step of demodulating the current or voltage signal according to the frequency components of the at least two channels to compensate for the magnitude of the output voltage. Claim 17 A signal processing method for a touchscreen panel according to claim 16, wherein the step of compensating the magnitude of the output voltage comprises: a step of extracting a signal of a component matching the frequency of the driving signal from the current or voltage signal; and a step of sequentially integrating the signal obtained by the extraction based on the multiple capacitors. Claim 18 A signal processing method for a touchscreen panel according to claim 17, further comprising the step of detecting position information of the touchscreen panel based on a demodulated digital capacitance signal in the step of compensating the magnitude of the output voltage. Claim 19 A computer-readable recording medium storing a computer program, wherein the computer program includes instructions for a processor to perform a signal processing method performed by a signal processing device of a touchscreen panel, and the method comprises: a step of generating a driving signal with reduced harmonic components based on a sinusoidal wave and applying the driving signal to the touchscreen panel; and a step of detecting a received signal of the touchscreen panel modulated by the driving signal; wherein the applying step includes a step of applying the driving signal having different frequencies to the touchscreen panel for each of at least two channels of the touchscreen panel, and the detecting step includes a step of detecting a change in capacitance of the touchscreen panel by sequentially integrating the received signal corresponding to the driving signal based on multiple capacitors, and the applying step includes a step of generating the driving signal by modulating the output voltage required in the applying step with the sinusoidal wave. A computer-readable recording medium comprising: a step of simultaneously applying the driving signal to the at least two channels; wherein the generating step comprises: a step of generating the sine wave by low-pass filtering a digital signal applied to the signal processing device; and a step of generating the driving signal in which harmonic components caused by the activation signal are reduced by modulating the supply voltage required in the step of generating the sine wave into the sine wave; thereby outputting the driving signal as a synthesis of the excitation signal of the sine wave and the activation signal; wherein the applying step comprises sequentially selecting the at least two channels and, by the selection, simultaneously applying the driving signal to the at least two channels; and, when the driving signal is simultaneously applied to the at least two channels, initializing the step of generating the driving signal as the at least two channels are sequentially selected. Claim 20 A computer program stored on a computer-readable recording medium, wherein the computer program includes instructions for a processor to perform a signal processing method performed by a signal processing device of a touchscreen panel, and the method comprises: a step of generating a driving signal with reduced harmonic components based on a sinusoidal wave and applying the driving signal to the touchscreen panel; and a step of detecting a received signal of the touchscreen panel modulated by the driving signal; wherein the applying step includes a step of applying the driving signal having different frequencies to the touchscreen panel for each of at least two channels of the touchscreen panel, and the detecting step includes a step of detecting a change in capacitance of the touchscreen panel by sequentially integrating the received signal corresponding to the driving signal based on multiple capacitors, and the applying step includes a step of generating the driving signal by modulating the output voltage required in the applying step with the sinusoidal wave. A computer program stored on a recording medium that includes the step of simultaneously applying the driving signal to the at least two channels; wherein the generating step comprises the step of generating the sine wave by low-pass filtering a digital signal applied to the signal processing device; and the step of generating the driving signal in which harmonic components caused by the activation signal are reduced by modulating the supply voltage required in the step of generating the sine wave into the sine wave; thereby outputting the driving signal as a synthesis of the excitation signal of the sine wave and the activation signal; wherein the applying step includes the step of sequentially selecting the at least two channels and simultaneously applying the driving signal to the at least two channels by the selection; and wherein, when the driving signal is simultaneously applied to the at least two channels, the step of generating the driving signal is initialized as the at least two channels are sequentially selected.

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